This disclosure relates to methods and systems for troubleshooting charging and photoreception failure modes associated with a xerographic process.
An electrophotographic, or xerographic, image printing system employs an image bearing surface, such as a photoreceptor drum or belt, which is charged to a substantially uniform potential so as to sensitize the surface thereof. The charged portion of the image bearing surface is exposed to a light image of an original document being reproduced. Exposure of the charged image bearing surface selectively dissipates the charge thereon in the irradiated areas to record an electrostatic latent image on the image bearing surface corresponding to the image contained within the original document. The location of the electrical charge forming the latent image is usually optically controlled. More specifically, in a digital xerographic system, the formation of the latent image is controlled by a raster output scanning device, usually a laser or LED source.
After the electrostatic latent image is recorded on the image bearing surface, the latent image is developed by bringing a developer material into contact therewith. Generally, the electrostatic latent image is developed with dry developer material comprising carrier granules having toner particles adhering triboelectrically thereto. However, a liquid developer material may be used as well. The toner particles are attracted to the latent image, forming a visible powder image on the image bearing surface. After the electrostatic latent image is developed with the toner particles, the toner powder image is transferred to a media, such as sheets, paper or other substrate sheets, using pressure and heat to fuse the toner image to the media to form a print.
An image printing system generally has two important dimensions: a process (or a slow scan) direction and a cross-process (or a fast scan) direction. The direction in which an image bearing surface moves is referred to as the process (or the slow scan) direction, and the direction perpendicular to the process (or the slow scan) direction is referred to as the cross-process (or the fast scan) direction.
Electrophotographic image printing systems may produce color prints using a plurality of stations. Each station has a charging device for charging the image bearing surface, an exposing device for selectively illuminating the charged portions of the image bearing surface to record an electrostatic latent image thereon, and a developer unit for developing the electrostatic latent image with toner particles. Each developer unit deposits different color toner particles on the respective electrostatic latent image. The images are developed, at least partially in superimposed registration with one another, to form a multi-color toner powder image. The resultant multi-color powder image is subsequently transferred to a media. The transferred multicolor image is then permanently fused to the media forming the color print.
In a xerographic system, two of the most common failure sources are the charge device and the photoreceptor. Unfortunately, failure of either of these two components often produces identical failure mode effects (observables). Thus, it is often very difficult to quickly resolve which of these two components is the source of an observed failure mode effect. Such ambiguity leads to issues in properly diagnosing and fixing customer machines in the field and therefore increased downtime, increased parts usage (swapping in new components to try to resolve the issue), and increased on-site time for field service technicians.